The aims of this research project are to study several aspects of ionic transport, fluid transport, membrane permeability, metabolic activity, plasma membrane biochemistry and related physiological parameters important in the maintenance of cornea and lens transparency. Isolated corneas and lens from amphibia, rabbit and rat will be used. In the cornea, the intent of this research is to provide a better understanding of the mechanisms by which metabolic activity, through its coupling to ionic transport, regulates the movement of fluid and corneal hydration. Membrane ATPases activity will be assayed and the effect of enzyme inhibitors will be compared with their effect on physiological parameters. The Na-Cl cotransport system will be studied in detail. In the lens, the intent is to characterize the relative role of lens fibers and lens epithelium in the control of ionic composition and in volume regulation. Membrane vesicles will be prepared from fibers and epithelium to characterize ion-selective pathways present in lens membranes. A model for the development of experimental cataracts based on the inhibitory effect of tryptamine on Na/K ATPase will be studied in detail. The following approaches will be utilized: Electrophysiological. Measurement of ionic fluxes, short-circuit current and PD with external and intracellular electrodes. Pharmacological. Study the effect of modifiers of the active transport such as catecholamines, ionophores, metabolic inhibitors, diuretics, etc. Biochemical. Fractionation of cell components, isolation of membranes, preparation of vesicles and enzyme assays. Theoretical-phenomenological. Classical electrical models, phenomelogical equations, and electrical analogues will be used to analyze the data.